中文摘要：

选择具有南方亚热带农业小流域典型代表性的江西省孙家小流域，运用WaSiM-ETH分布式水文模型，模拟了该农业小流域的水文过程，并在流域尺度上估算了壤中流流量。研究结果表明，虽然孙家小流域土地利用方式多样，水文过程复杂，但是WaSiM-ETH模型仍显示了相当高的准确性。WaSiM-ETH模型模拟孙家小流域出口年径流量的相对误差为3．7％-4．3％，决定系数（R。）高达0．96。在模型模拟的2002年-2003年期间，孙家小流域年蒸散量为672-804mm，占年降雨的39．6％-52．5％；小流域壤中流年径流量为542-666mm，占年降雨输入的35．4％-39．2％，高于地表径流的8．8％-21．4％。这说明WaSiM-ETH模型在该地区流域水文过程模拟方面具有很高的适应性，其不仅能够准确模拟南方亚热带农业小流域的地表水文过程，同时还能在流域尺度上估算壤中流流量。

英文摘要：

A typical subtropical agricultural catchment named Sunjia catchment in Jiangxi province was chosen and the WaSiM-ETH distributed hydrological model was employed to simulate hydrological processes and to quantify interflow at catchment scale. The results suggested that the WaSiM-ETH simulation showed acceptable accuracy and precision in simulation although there were complicated hydrological processes and various land use types in the studied catchment. Relative error of the simulated to measured outflow varied from 3.7% to 4.3% , and linear regression determining coeffi- cient （R2 ） reached as higher as 0.96. During the period of 2002 - 2003, the model predicted annual evapotranspiration ranged from 672 mm to 804 mm, accounting for 39.6%-52.5% of annual precipitation. Annual interflow of the catch- ment ranged from 542 mm to 666 mm, took 35.4%- 39.2% parts of annual precipitation, being higher than 8.8% - 21.4% of ratio for annual overland flow. Based on our collective data in this study, we may conclude that the WaSiM- ETH model is flexible and capable of the hydrological simulation in subtropical agricultural catchments as it can not only model the surface hydrological process, but also quantify interflow at catchment scale.